This invention is concerned with a filling or metering valve for use in filling flexible bags with viscous fluids, such as with cream, yoghurt, honey, fruit juices, medicines and other viscous products.
The process of filling flexible bags with viscous substances, particularly foods, has been difficult to automate. Firstly, the very viscosity of the material requires injection under pressure. Secondly, it is necessary that a vacuum is preliminarily made in the bag, in order to avoid that air pockets are trapped inside it. Lastly, considerations of convenience require that the bag is only filled up to a certain level, a sterile, non-oxidizing atmosphere (typically nitrogen) being formed above it.
These steps should be completed while preventing the product both from dripping outside the bag and soiling it and from leaking into undesired areas of the equipment, so as to avoid, on the one hand, that the product causes clogging of the duct, which would adversely affect the operation of the apparatus, and also, on the other hand, that hotbeds of bacterial proliferation may develop in places that are difficult to access and therefore difficult to sanitize. Known filling bags achieve one or the other of the aims above, but they generally fail to satisfy all requirements.
It is the main object of the invention to provide a filling valve for flexible bags, by which a predetermined dose of a fluid substance, even of a high viscosity, can be injected into a bag, with preliminary suction and subsequent introduction of an inert gas, and while preventing the viscous product both from dripping onto the bag and from coming into contact with pairs of the valve not directly belonging to its path.